Screen for use in oscillating screening devices



A. WEHNER March 6, 1962 SCREEN FOR USE IN OSCILLATING SCREENING DEVICES2 SheetsSheet 1 Original Filed March 15, 1954 FIG.2

lberrvvenner A INVENTOR.

March 6, 1962 A. WEHNER 3,023,904

SCREEN FOR USE IN OSCILLATING SCREENING DEVICES Original Filed March 15,1954 2 Sheets-Sheet 2 FEG.4

Alberr Wehner INVENTOR.

Unit t 1 Claim. Cl. 209-396) This application is a division ofapplication Serial No. 416,318, now Patent No. 2,870,910.

The invention relates to oscillating screens and sieves; it particularlyrelates to oscillating screens and sieves provided with adjacentlyspaced bars formed preferably on both sides, with lateral projections.

It is an important object of the invention to impart to screens andsieves of the above-mentioned type a high grade of self-cleaningefliciency.

It is a further object of the invention to create a very large screeningsurface and to improve the screen openings in such a manner that asatisfactory grain classification of the materials to be screened isattained even in those cases where these materials are interspersed withrod-shaped pieces, such as wood fibers.

The customary screens and sieves do not satisfy the above-mentionedobjects. Even if, for instance, perforated sheet-metal screens havecertain advantages with regard to durability, simplicity of constructionand shape retention of their openings and perforations, they possess thedisadvantage of having a restricted open screen surface and, above all,they are rigid and therefore not selfcleaning.

The situation with known fabric screens is different.

Here the shape of the screen openings is changeable to a certain extentand the open screen surface is relatively large; on the other hand,their self-cleaning ability, their resistance to wear and the loadingcapacity of these fabric screens is insufiicienta The known perforatedscreens consisting of adjacent profiled bars have the disadvantage of apoor classification of the charged materials and, in particular, cannotbe used to screen rod-shaped materials.

Screens are known which consist of profiled rods provided with shortlateral extensions, the latter being oppositely located to each otherand acting as distance pieces. Such screens, however, are extremelystiff and rigid; moreover, stoppages, which considerably interfere withthe output of the screen, are the rule with these screens.

It is thus another object of this invention to eliminate theabove-recited disadvantages and drawbacks of conventional screen types.

With this purpose in view, bar-shaped screen members are used inconformity with this invention and the same are provided with transverseor lateral extensions which are disposed in such a manner that thelateral projections of one screen member are received between the crossbars of the adjacent screen members; the screen members arealternatingly mounted in two relatively movable frame members which arelocated on oscillating links, rods, springs or the like and connected insuch a manner that they move parallel to one another during theiroscillation. The system has been disclosed, but

3,023,904 Patented Mar. 6, 1962 not claimed, in US. Patent No. 2,870,910issued on a formerly co-pending application.

These screen members may be used in the form of profiled bars and thetwo frame-forming members may be mounted and driven by suitably arrangedcrank shafts in such a manner that the lateral projections of twoadjacent profile bars and therefore of different frames are movableabout a common axis of rotation, or that the lateral extensions of theone frame move around those of the other frame.

The invention will now be described more in detail and with reference tothe accompanying drawing, where- 1n:

FIG. 1 is a perspective view of a screen according to the inventioncomposed of oscillating screen sections;

FIGS. 2 and 3 are diagrammatic views illustrating various modes ofoscillating the screen shown in FIG. 1; and

FIGS. 4 and 5 are fragmentary top-plan views (parts broken away) of thescreen of FIG. I mounted for oscillatory movement in keeping with FIGS.2 and 3, respectively.

As is apparent from FIG. 1 the screen has two frame members 8, 9 and itslongitudinal bars 1, 2 arerespectively connected to these outer framemembers 8, 9 by rails 6, 6 which are either Welded to the bars 1, 2 orotherwise connected therewith.

The two movable frame members or bars 8, 9 are connected with each otherby oscillating means, such as the crank shafts 10 (FIG. 4) or 10a (FIG.5), in such a manner that the interstices 11 enclosed by the adjacentlongitudinal bars 1, 2 and their lateral extensions 3, 4 areperiodically changed with regard to size and shape. In this manner ahighly desirable self-cleaning action is attained, and work interruptiondue to clogging of the screen passages is prevented.

The two frame bars 8, 9 may be mounted and driven in such a manner thatthe interengaging lateral extensions 3, 4 carry out the movementsdiagrammatically illustrated in FIGS. 2 and 3.

By the application of suitable driving means to the crank shafts 10 or1011, as schematically illustrated in dot-dash lines in FIGS. 4 and 5,the lateral extensions 3 may make circular movements about theirposition of rest or about the stationary lateral extensions 4, as shownin FIG. 3.

Thus, the frame members 8, 9 with the sets of profiled bars 1, 2respectively carried thereon may be mounted, as illustrated in FIG. 4,on a support 23 in which the crank shafts 10 are journaled eccentricallyso that both frames 8 and 9 execute translational movements causing theextensions 3, 4 to revolve about common axes 12 as shown in FIG. 2. Theymay, however, also have crank shafts 10a journaled in a support 2311concentrically with respect to frame 9, as shown in FIG. 5, whereby theextensions 3 revolve about the extensions 4 as illustrated in FIG. 3.

From FIGS. 1, 4 and 5 it will be apparent that the rails 6 pass freelyunderneath bars 2 while being secured to bars 1 at 13 and to frame 8 at14; conversely, rails 6' pass freely underneath bars 1 while beingconnected with bars 2 at 15 and with frame 9 at 16.

Since certain changes may be made in the above invention and differentembodiments of the same could be made without departing from the scopethereof, it is intended that all matter contained in the abovedescription or shown in the accompanying drawing shall be interpreted asillustrative and not in a limiting sense.

What I claim is:

A screen for use in oscillating screening devices, comprising a firstand a second set of longitudinal profiled bars spacedly located next toand alternating with one another, said profiled bars being provided withlateral extensions which are positioned in intermeshed relationship witheach other, and crank-shaft means for so displacing said sets relativeto each other while maintaining said profiled bars parallel to oneanother that the extensions on each of said bars of one set rotatearound the lateral extensions of the adjacent bars of the other set.

Jensen et al Sept. 15, 1925 Symons Sept. 6, 1932

